Numerous products exist to provide the basic function of automatically activating an aerosol can. One such type of product is an air freshener that automatically dispenses or can be programmed to periodically dispense a small quantity of the contents of the aerosol can into a room.
The majority of aerosol dispensing products or dispensing systems allow an aerosol can to be secured within the dispensing system and thereafter automatically activate the aerosol can such that a specific and small quantity of product can be dispensed per activation. In a typical air freshener type system, the dispenser system is usually designed as a cabinet to be mounted on a wall in which the aerosol can is hidden from view behind an opening door that can be opened to replace an aerosol can. The dispensing system will typically include a power source and controller that activates an electromechanical gear and hammer assembly that presses down on the nozzle of the aerosol can in order to periodically release the aerosol can contents. The controller may allow a user to program the dispensing frequency and volume. The devices are typically battery powered and use timers to turn the activation systems on and off.
A significant problem with past designs of dispensing systems is that the aerosol refill cans used in these dispenser systems have different sizes which leads to a number of operational problems that are discussed below.
For example, while most aerosol cans are manufactured from standard tinplate steel or aluminum, the large number of different manufactures, products being dispensed and sheer volume of aerosol cans being manufactured results in a wide range of sizes of aerosol cans. That is, while aerosol cans are mass produced in “industry standard” sizes, the lack of criticality in maintaining defined tolerances in the size of the cans results in industry standard sized cans varying significantly from manufacturer to manufacturer. This is particularly true with aluminum cans where the heights of a “standard” can in fact vary significantly. These differences can often be as much as several millimeters which, depending on the final use/operation of the can, may be of no importance or lead to various problems as described herein.
In particular, if an aerosol can is simply hand-held, differences in sizes between aerosol cans is of no importance. As such, as many aerosol can products are designed for hand-held use, minor variances in height are generally not important to the majority of product applications and, as such, the manufactured sizes do not need to be tightly controlled. As most aerosol cans are still used in this manner, there has been not been a need for manufacturers to shift their manufacturing practices. However, fitting different sizes of aerosol cans into a standard size dispensing system can be problematic.
Aerosol Can Valve Mechanisms
As is also known, aerosol cans have valve and nozzle mechanisms that are used to physically dispense product from the aerosol can. In a typical design, a cylindrical tube having a bottom is fitted with a domed cap containing a valve apparatus. As shown in FIG. 1, (A) showing a valve closed and (B) showing a valve open, the valve apparatus typically includes a valve mounting cup 1 that is sealed to or forms part of the domed cap. The valve mounting cup retains a valve housing 1a and a gasket 2 through which a valve stem 3 protrudes, the valve stem having an exterior side and an interior side. The exterior side is substantively a hollow tube to which an actuator 4 is attached. The actuator will normally be press fit over the valve stem and provides a 90° re-direction of can contents passing through the valve stem and an orifice insert 5. The exterior side of the valve stem contains a perpendicular orifice located at or above the sealing gasket. The interior side of the valve stem is fitted with a spring cup 6 that is normally biased against the gasket by a spring 7 such that the spring cup is sealed against the gasket and prevents the release of can contents. The base of the interior side will serve as a plug. The valve housing 1a contains an interior chamber that is normally open to the pressurized contents of the can through a dip tube 8 that carries the aerosol can contents from the bottom of the can to the valve mechanism. When the actuator and valve stem are depressed against the spring (B), the orifice in the stem descends below the gasket such that the can contents in the reservoir can flow through the orifice insert and out of the can. Simultaneously, the base of the stem may seat in the bottom of the reservoir, stopping the flow of can contents through the dip tube. Thus, in this case, only the can contents that were resident in the reservoir are allowed to escape through the orifice in the valve stem. When pressure on the actuator and valve stem is released, the spring will cause the spring cup to move against the gasket in order to reseal the valve cup and gasket and prevent the flow of can contents while the base of the stem is lifted to allow the contents of the can to recharge the reservoir in the valve (if present). The spring is contained within a valve housing that is supported by the valve cup. Aerosol cans may also be fitted with metered valves with dosing cups to provide fixed volume dosing of product.
As an aerosol can is generally a disposable product, the life of the valve mechanism is designed to last for an estimated number of actuations when operated within typical operating parameters. As a result, valve mechanisms may be subject to failure beyond a certain number of actuations and/or abnormal operation of the valve mechanism. In particular, one specific problem for aerosol cans that are mounted within dispensing systems, is that repeated actuation of the valve in an off-axis direction may lead to premature failure of the valve should the gasket, valve stem or spring cup fail.
In a metered installation, a metered valve will be used to allow a typical aerosol to deliver between 3000 and 9000 activations. With an automatic dispenser, as the can does not move between actuations, off-centered or nonlinear activation that is repeated over and over again results in a lateral force being applied to the same point of valve stem and seal of the valve. This repeated stress will often cause the valve stem seal to fail and leak at some point prior to the can being depleted of its contents allowing the gas and can contents to escape around the stem. Within the industry, this is called bypass.
At the very least, the failure of a seal resulting in leakage of can contents can be messy and time-consuming to clean up. Leakage may also cause the system to not operate properly as a result of residues building up around the valve stem. More importantly, seal failure will often result in damage to the dispensing apparatus from the solvents within the aerosol cans. As the dispensing apparatus is the more expensive component, it is obviously desirable to prevent damage to this type of equipment.
A related problem occurs when the valve is not properly activated and the spray is not fully atomized. Since the dispenser is mounted in a fixed position any dripping or sputtering of the spray can result in accumulation of the fragrance formula on the dispenser cover or the floor directly in front of the dispenser. Since aggressive solvents are used in fragrance formulations, this accumulation of material can also damage the surface of the cover or floor.
Size and Configuration Problems and Past Solutions
Supply Chain Problems
Furthermore, the dispensing systems used with aerosol cans are usually proprietary designs unique to each manufacturer. As a result of differences in aerosol can sizes as discussed above, these size differences often require that the manufacturer of the dispenser and aerosol refill system (eg. an air freshener system) to standardize with a specific can and valve supplier in order to ensure that the can will fit and operate properly in a particular manufacturer's dispenser(s).
Since refill components are costly and space consuming, it is often difficult to maintain sufficient inventory reserves to ensure against interruption of supply particularly with tinplate which is a commodity that can be in limited supply. As a result, interruptions of supply to the market are frequent which often results in a loss of immediate and future business.
As a result, this often makes it difficult for the manufacturer to switch aerosol can suppliers when the supply of a particular aerosol can is in short supply or no longer economical. Moreover, as is known, once customers have switched suppliers it is often difficult to regain their business.
Shelves and Yokes
In some systems, manufacturers have addressed the can height issue by providing a shelf that can be removed to accommodate a larger can. Other manufacturers attempt to secure the can in the dispenser with a yoke device that supports the can at the neck.
The use of shelves in dispensers also has a poor compliance rate. Customers generally require foolproof systems that can be serviced and maintained with a minimum of complexity. Untrained service personnel generally do not have the inclination and/or patience to fiddle with dispensers or refills to make them work.
Furthermore, the use of a neck ring or yoke requires close monitoring in the manufacturing process to ensure that the can will slide into the dispenser easily. Importantly, there is often a tolerance stack up problem with the valve, can and crimping process that can significantly reduce the gap between the valve and the can that fits onto the yoke in the dispenser. This constriction of the gap results in cans that are difficult to install and/or difficult to remove. Further still, as these dispensers are typically installed at a height of around seven feet from the floor, service personal are often unable to remove the can without mounting a ladder and may even pull the dispenser off the wall in their attempts to remove the can. As such, there has been a need for systems where access to batteries is provided at a lower height so as to minimize the complexity and time required to replace batteries.
Keying Between Can and Dispenser
Another significant concern of dispenser manufacturers is the use of unauthorized refills within one manufacturer's dispenser. That is, as it is more expensive to design and build a dispenser, a manufacturer will generally want to ensure that authorized aerosol cans are used within a specific dispenser. However, as the aerosol refills are manufactured with standard components it becomes relatively easy for competitors to produce refills that will operate in another's dispenser. This practice results in the loss of annuity income from refill sales along with potential performance problems and damage to the dispenser associated with the use of unauthorized refills. Thus, there has been a need for a system that prevents the use of unauthorized refills.
Past attempts to prevent the use of unauthorized cans have been the use of specific mechanical designs of nozzles and/or mechanical keys that obstruct or prevent “regular” can designs to be mounted within a dispenser. However, many of these systems can be overcome by physically modifying the “regular” can to fit a dispenser with a key system.
Employing mechanical keys to eliminate the use of unauthorized refills has only marginal success. These keys tend to annoy customers, interfere with the activation of the can and can often be easily overcome with a few strokes of a utility knife.
Power Consumption
Another type of problem with automatic dispensers is power consumption. As the majority of automatic dispensers are battery operated, in the commercial and industrial markets, service costs are an important factor in choosing an automatic dispensing system such as an air care system. For example, in the case of automatic air fresheners and as noted above, a dispenser is usually located high on a wall in order to avoid tampering by the public. As a result, if access is difficult, changing batteries can be difficult and time consuming. In most cases, a minimum of one year battery life is expected by most customers and many existing dispensers fail to meet this requirement.
The majority of dispensers in the market use similar activation mechanisms. These mechanisms consist of a small DC motor mounted to a motor mount plate with a series of plastic gears. The final gear is a hammer gear that actuates the valve by pressing on the nozzle or actuator of the aerosol can. The hammer gear forces the valve open and continues to pressure that valve until the motor stalls and/or a predetermined interval is reached and the mechanism stops. These mechanisms usually rely on the valve spring to reset the gear to their initial state.
While such mechanisms are effective, they are also inefficient with respect to power consumption. Moreover, such systems may also apply substantially off-center forces on the valve stem.
The hammer mechanism previously described is not particularly efficient as it requires additional stroke length to compensate for the differences in height of the can and to ensure a complete actuation. This often creates a condition where the motor is stalled. This condition can create a tenfold increase current consumption and exert uneven and excessive force on the valve stem. In these systems, the power consumption is particularly inefficient when the batteries are fresh and the voltage is higher as such systems do not monitor battery voltage and only use a fixed time interval to turn a motor on and off.
Programming
Further still, dispensing apparatus have controllers that are programmed to dispense product at various intervals. The controllers may include various sensors and/or modes of operation that provide various functionalities to the dispenser. For example, dispensers may be programmed to dispense at regular intervals based on an internal clock that is programmed by the user. In this case, a user at the time of installation would program the time into the controller and then typically select a specific time interval for dispensing depending on the anticipated need. Such intervals may be presented as 10, 20, 30 minute time intervals for example. In order to overcome the problem of dispensing when people are not around, past systems have included light or motion sensors into the dispensing apparatus such that dispensing will only occur if the lights in the room are on or movement is detected. However, as is well known, in many installations, lights may be left on 24 hours a day that may result in over-dispensing and/or motion sensing that may result in dispensing that is under-correlated to actual person volumes.
Similarly, such systems may include programs that signal that service may be required based on a pre-set time interval.
While some systems may be programmed by the user to establish a time reference for determining a dispensing frequency, research has indicated that the relatively simple steps of programming a time into a unit is very often not undertaken thus preventing any resident dispensing programs from being logically referenced to a desired dispensing frequency by the controller. For example, if a program changes dispensing frequency from daytime to nighttime, an improperly referenced time will render changes in frequency irrelevant.
Furthermore, any more complicated programming steps are unlikely to be completed during installation or at other times.
Accordingly, there has been a need for systems that overcome the above problems.